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Mars atmospheric entry is the entry into the atmosphere of Mars. High velocity entry into Martian air creates a CO2-N2 plasma, as opposed to O2-N2 for Earth air.〔(J. Louriero, et al. - Atmospheric Entry Research at the Plasma Physics Centre )〕 Mars entry is effected by the radiative effects of hot CO2 gas and Martian dust suspended in the air.〔(R. M. Haberle, et al. - A boundary-layer model for Mars - Journal of the Atmospheric Sciences )〕 Flight regimes for entry, descent, and landing systems include aerocapture, hypersonic, supersonic, and subsonic.〔(Development of Supersonic Retro-Propulsion for Future Mars Entry, Descent, and Landing Systems ) (.pdf)]〕 Thermal protection systems and atmospheric friction have been used historically to reduce most of the kinetic energy that needs to be lost prior to landing, with parachutes and, sometimes, a final bit of retropropulsion used in the final landing. High-altitude high-velocity retropropulsion is being researched for future transport flights landing heavier cargos. For example Mars Pathfinder entered in 1997.〔(Mars Pathfinder Atmospheric Entry Strategy - NASA )〕 About 30 minutes prior to entry, the cruise stage and entry capsule separated.〔 When the capsule hit the atmosphere it de-accelerated from about 7.3 km/s to 0.4 km/s (16330 mph to 900 mph) over three minutes.〔 As it descended the parachute opened to slow it down further, and soon after the heat shield was released.〔 During entry a signal was relayed back to Earth, including semaphore signals for important events.〔 ==Examples== *Mars 2 *Mars 3 *Mars 6 *Viking 1 *Viking 2 *Mars Pathfinder *MER-A *MER-B *Phoenix lander *Mars Science Laboratory 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mars atmospheric entry」の詳細全文を読む スポンサード リンク
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